293. When is it possible to give Holy Communion to other Christians?

293. When is it possible to give Holy Communion to other Christians? 

(Comp 293) Catholic ministers may give Holy Communion licitly to members of the Oriental Churches which are not in full communion with the Catholic Church whenever they ask for it of their own will and possess the required dispositions. Catholic ministers may licitly give Holy Communion to members of other ecclesial communities only if, in grave necessity, they ask for it of their own will, possess the required dispositions, and give evidence of holding the Catholic faith regarding the sacrament.

“In brief”  

(CCC 1401) When, in the Ordinary's judgment, a grave necessity arises, Catholic ministers may give the sacraments of Eucharist, Penance, and Anointing of the Sick to other Christians not in full communion with the Catholic Church, who ask for them of their own will, provided they give evidence of holding the Catholic faith regarding these sacraments and possess the required dispositions (CIC, can. 844 § 4).

To deepen and explain   

(CCC 1399) The Eastern churches that are not in full communion with the Catholic Church celebrate the Eucharist with great love. "These Churches, although separated from us, yet possess true sacraments, above all - by apostolic succession - the priesthood and the Eucharist, whereby they are still joined to us in closest intimacy." A certain communion in sacris, and so in the Eucharist, "given suitable circumstances and the approval of Church authority, is not merely possible but is encouraged" (UR 15 § 2; cf. CIC, can. 844 § 3). 

On reflection  

(CCC 1400) Ecclesial communities derived from the Reformation and separated from the Catholic Church, "have not preserved the proper reality of the Eucharistic mystery in its fullness, especially because of the absence of the sacrament of Holy Orders" (UR 22 § 3). It is for this reason that Eucharistic intercommunion with these communities is not. However these ecclesial communities, "when they commemorate the Lord's death and resurrection in the Holy Supper… profess that it signifies life in communion with Christ and await his coming in glory" (UR 22 § 3).   

(Next question: Why is the Eucharist a “pledge of future glory”?)